Quiz for Balancing redox

Q1: Which method is generally used to balance redox reactions in acidic medium?

A. Ionic-electron method B. Oxidation number method C. Half-reaction method D. All of the above

Q2: In redox reactions, what is conserved?

A. Atoms only B. Charge only C. Both atoms and charge D. Neither atoms nor charge

Q3: Balance the equation: MnO₄⁻ + Fe²⁺ → Mn²⁺ + Fe³⁺ in acidic medium. What is the coefficient of Fe²⁺?

A. 5 B. 1 C. 2 D. 3

Q4: In basic medium, which ion is added to balance hydrogen?

A. OH⁻ B. H⁺ C. H₂O D. e⁻

Q5: In acidic medium, which ion is used to balance oxygen?

A. H₂O B. O²⁻ C. H⁺ D. OH⁻

Q6: In acidic medium, which species is used to balance hydrogen atoms?

A. H₂O B. H⁺ C. OH⁻ D. e⁻

Q7: In the reaction: Cr₂O₇²⁻ + I⁻ → Cr³⁺ + I₂, what is the oxidizing agent?

A. I⁻ B. Cr³⁺ C. Cr₂O₇²⁻ D. I₂

Q8: What is the change in oxidation number of sulfur in H₂S → SO₂?

A. -2 to +4 B. 0 to +6 C. +2 to -2 D. +4 to -2

Q9: The total increase in oxidation number must equal the total _____ in a redox reaction.

A. Electron gain B. Electron loss C. Mass increase D. Charge increase

Q10: Which method involves writing oxidation and reduction half-reactions?

A. Ion-electron method B. Inspection method C. Titration method D. Spectroscopy

Q11: Balance: H₂O₂ → H₂O + O₂ in basic medium. What is the coefficient of H₂O?

A. 2 B. 1 C. 3 D. 4

Q12: Which species is reduced in the reaction: Zn + Cu²⁺ → Zn²⁺ + Cu?

A. Zn B. Cu C. Cu²⁺ D. Zn²⁺

Q13: Which species is oxidized in the reaction: Cl₂ + 2NaI → 2NaCl + I₂?

A. NaI B. Na⁺ C. Cl₂ D. I₂

Q14: Which balancing method uses oxidation numbers?

A. Oxidation number method B. Ion-electron method C. Half-reaction method D. Neutralization method

Q15: How many electrons are transferred in the reaction: Fe²⁺ → Fe³⁺?

A. 1 B. 2 C. 3 D. 0

Q16: Which reaction is not a redox reaction?

A. Zn + HCl → ZnCl₂ + H₂ B. H₂ + Cl₂ → 2HCl C. NaOH + HCl → NaCl + H₂O D. Fe + CuSO₄ → FeSO₄ + Cu

Q17: In redox titration, what acts as the titrant?

A. Reductant B. Oxidant C. Base D. Salt

Q18: What is the oxidation number of O in H₂O₂?

A. -2 B. 0 C. -1 D. +1

Q19: Balance the reaction in acidic medium: HNO₃ → NO₂ + H₂O. What is the coefficient of HNO₃?

A. 2 B. 3 C. 4 D. 1

Q20: In the redox reaction, which factor helps identify reduction?

A. Gain of oxygen B. Loss of hydrogen C. Gain of electrons D. Loss of electrons

Q21: In acidic medium, which species is used to balance oxygen?

A. OH⁻ B. O²⁻ C. H₂O D. H⁺

Q22: What is the oxidation number of Cr in Cr₂O₇²⁻?

A. +6 B. +7 C. +3 D. +4

Q23: Which method is used for balancing redox reactions in basic medium?

A. Oxidation number method B. Half-reaction method C. Ionic method D. Redox number method

Q24: In basic medium, which ion is used to balance hydrogen?

A. OH⁻ B. H⁺ C. H₂O D. O²⁻

Q25: Which of the following is a disproportionation reaction?

A. 2H₂ → 2H⁺ + 2e⁻ B. Cl₂ + 2OH⁻ → ClO⁻ + Cl⁻ + H₂O C. Fe³⁺ + e⁻ → Fe²⁺ D. Zn → Zn²⁺ + 2e⁻

Q26: The oxidizing agent is the species that:

A. Loses electrons B. Gains electrons C. Gets reduced D. B and C

Q27: Which element is oxidized in the reaction: Zn + Cu²⁺ → Zn²⁺ + Cu?

A. Zn B. Cu C. Zn²⁺ D. Cu²⁺

Q28: In KMnO₄, the oxidation state of Mn is:

A. +2 B. +4 C. +7 D. +6

Q29: What is the oxidizing agent in the reaction: H₂O₂ → H₂O + O₂?

A. O₂ B. H₂O C. H₂O₂ D. None

Q30: Which of the following reactions is not redox?

A. HCl + NaOH → NaCl + H₂O B. Zn + CuSO₄ → ZnSO₄ + Cu C. Fe + Cl₂ → FeCl₃ D. C + O₂ → CO₂

Q31: Which method is commonly used to balance redox reactions in acidic medium?

A. A) Half reaction method B. B) Ion-electron method C. C) Oxidation number method D. D) Both A and B

Q32: In redox reactions, oxidation involves:

A. A) Gain of electrons B. B) Loss of electrons C. C) No electron transfer D. D) Gain of protons

Q33: In acidic medium, which species is used to balance oxygen atoms?

A. A) OH⁻ B. B) H⁺ C. C) H₂O D. D) O₂

Q34: Balance the redox reaction: Zn + H⁺ → Zn²⁺ + H₂. Which is oxidized?

A. A) Zn B. B) H⁺ C. C) H₂ D. D) Zn²⁺

Q35: In the reaction: Fe²⁺ → Fe³⁺ + e⁻, what type of process is it?

A. A) Oxidation B. B) Reduction C. C) Disproportionation D. D) Neutralization

Q36: What is the change in oxidation number of Mn in MnO₄⁻ → Mn²⁺?

A. A) +7 to +2 B. B) +2 to +7 C. C) +6 to +2 D. D) +4 to +2

Q37: In basic medium, oxygen atoms are balanced using:

A. A) H₂O only B. B) OH⁻ only C. C) H⁺ only D. D) H₂O and OH⁻

Q38: Which of the following is not a redox reaction?

A. A) Zn + Cu²⁺ → Zn²⁺ + Cu B. B) H₂ + Cl₂ → 2HCl C. C) NaCl + AgNO₃ → AgCl + NaNO₃ D. D) 2Fe³⁺ + Sn²⁺ → 2Fe²⁺ + Sn⁴⁺

Q39: In redox reactions, reducing agent undergoes:

A. A) Oxidation B. B) Reduction C. C) No change D. D) Proton gain

Q40: When H₂O₂ acts as oxidizing agent, what is its product?

A. A) H₂O B. B) O₂ C. C) H⁺ D. D) H₂O + O₂

Q41: What is the oxidation number of Mn in KMnO₄?

A. +2 B. +4 C. +7 D. +5

Q42: In balancing redox reactions in basic medium, what is added to balance H⁺?

A. HCl B. H₂O C. OH⁻ D. H₂

Q43: Which is a disproportionation reaction?

A. Cl₂ + 2NaOH → NaCl + NaClO + H₂O B. H₂ + Cl₂ → 2HCl C. Zn + Cu²⁺ → Zn²⁺ + Cu D. Fe + S → FeS